1. Field of the Invention
The present invention is broadly concerned with dual-component fertilizer materials and methods of use thereof wherein the fertilizer material provides enhanced yields of crops. More particularly, the present invention is concerned with such fertilizer materials comprising a first fertilizer product including an ammoniacal fertilizer and a partial calcium salt of a copolymer, along with a second fertilizer product including a phosphorous fertilizer and a partial sodium salt of a copolymer; the first and second fertilizer products are used in synergistically effective amounts in order to increase crop yields.
2. Description of the Prior Art
Plants have been fertilized with various materials since the dawn of agriculture. Fertilizers have included manure products as well as ammoniacal nitrogen materials (e.g., anhydrous ammonia and urea), and phosphorous fertilizers such as ammonium polyphosphate and other products derived from phosphate rock. A worldwide industry provides modern-day fertilizers of desired N—P—K grades in a bewildering variety of combinations.
In recent years a series of U.S. patents have issued describing biodegradable polymers having significant agricultural facilities, particularly when used in combination with conventional fertilizers. For example, U.S. Pat. No. 6,515,090 describes dicarboxylic copolymers made up, e.g., of moieties of itaconic acid and maleic anhydride. This patent also discloses that such copolymers may be partially neutralized with metal or other cations, and can be used to form composite products with fertilizers. These combined fertilizer-copolymer products have been shown to increase the availability of phosphorous for uptake by growing plants, and can be applied to soil adjacent the plants or in foliar applications. Polymers in accordance with the '090 patent are commercially available from Specialty Fertilizer Products of Belton, Mo. under the designations NUTRISPHERE-N® and AVAIL®.